The present invention relates generally to vacuum collectors of the mobile, vehicular type. More particularly, the invention relates to an improved boom height adjustment mechanism.
In applicant's prior U.S. Pat. No. 3,710,412, entitled "Vacuum Trash Collector," issued Jan. 16, 1973, a cart-mounted, mobile trash collector is illustrated and described. The trash collector employs a flexible hose of inverted U-shape which has a nozzle on its outer end and which is connected at its inner end to the lid of the collection canister or bin. The hose is supported by a leaf spring pivoted at its inner end and the nozzle is controlled by a handle through a telescoping connection.
In applicant's referenced prior patent the leaf spring mechanism was carried on a bracket secured to the inlet portion of the bin lid. The leaf spring assembly was pivotally connected to the bracket to allow pivotal movement about the axis of the coaxial pivots. Up and down movement of the nozzle relative to the surface of the ground was effected by flexing the leaf spring mechanism.
Although the device described in applicant's referenced prior patent permitted the nozzle to be moved to a variety of different positions, the up/down movement, by the nature of the structure employed, required the human operator to flex the leaf spring assembly, which could get tiring for some operators after a full day of use.
To minimize operator fatigue, it would be desirable to establish the nozzle height above the ground in the optimal position, neither too high nor too low. If the nozzle is too high, the operator is constantly flexing the leaf spring assembly downwardly to reach the trash. If the nozzle is too low, the operator will frequently need to flex the leaf spring assembly upwardly to prevent the nozzle from engaging the ground while the vehicle is moving. In prior art devices, including the device illustrated and described in applicant's referenced issued patent, the nozzle height was simply the result of the stiffness of the leaf spring assembly vis-a-vis the weight of the flexible hose, nozzle and the operator's arm. Due to differences in operator body weight, the optimal nozzle height was not always achieved. Thus some prior systems have employed mounting bolts which could be loosened with a wrench to allow manual adjustment of the leaf spring assembly and then retightened for use. Because tools were required and because of the trial and error involved, it was not practical to adjust the nozzle height while the trash collector was in use in the field.
The present invention provides a greatly improved boom height adjustment which employs a combined pivot coupling and a reciprocative coupling. Preferably the pivot coupling and reciprocative coupling are incorporated in a bracket structure by which the boom may be attached to the collection canister or to another fixed location on the vacuum trash collector or its vehicle. A threaded driving means is mounted in fixed relation to the bracket and is operatively coupled to the boom for raising and lowering the height of the nozzle by effecting rotational movement of the boom about the pivot coupling.